Method of treating coal



I producer because this 30 only one of The-iron in the Patented Nov. 11, 1930 UNITED STATES.

PATENT OFF-ICE ERNEST VICTOR COLLINS, JR., OF BROOKLYN, NEW YORK, ASSIGNOR TO DELAWARE,

LACKAWANNA & WESTERN OF NEW JERSEY No Drawing.

This invention relates to the treatment of storage anthracite coal to remove therefrom the surface discoloration which takes place in storage and to restore essentially the original appearance of the fresh mined coal. Fresh mined coal, that is coal which is mined and shipped for-immediate consumption, has a jet black color and a bright luster. Owing to the seasonal demand for coal, large quantities of fresh'mined coal are placed in storage whenever possible in order to avert a shortage in the fall and winter months. Such coal is known in the trade as storage coal.

Coal so stored does not deteriorate as a fuel but the physical appearance is altered. The coal becomesa dull grey in appearance, and a considerable portion of it becomes badly discolored by metallic compounds. The consuming public, who are accustomed'to recognize anthracite coal by its jet black color and luster, often assume that coal which has been held in storage and has thus lost its characteristic appearance is poor in quality. The original fresh mined coal appearance cannot be restored by ordinary washing. Consequently serious losses are sustained by the storage coal does not command the price of fresh mined coal, although analysis indicates that the change is appearance and there is" no loss of fuel'value or consequential change in chemical composition. o mineral matter of coal is considered to be almost wholly present in combination with sulphur. Under the influence of atmospheric exposure the iron sul-.

phides become oxidized presumably to "insoluble basic, sulphates, oxides, and other compounds imparting to the coal a rusty appear- 4Q ance. Other reactions go on and other metallic compounds may show on the surface.

The longer the coal is in storage and consequently the longer it is exposed to atmospherlc influences, the greater usually be comes the discoloration.

COAL COMPANY, OF NEW YORK, N. Y., CORPORATION METHOD or TREATING coAr.

\ 'A pIication filed February 14, 1930. Serial No. 428,494.

It is the object of the present invention to provide a method of treating storage coal to remove the surface discoloration and restore solution at normal atmospheric temperatures 1 for a period sufficient to accomplish the object, usually a few minutes, after which the coal is removed from the solution and may be washed or sprayed with water. The solution may be heated to any desired temperature to accelerate the reaction. .The strength of the solution employed may vary widely depending upon the. degree of discoloration of the coal.

The action is more rapid and thorough if the coal is agitated in the solution, thereby producing a scrubbingaction. A practical means of accomplishing this action is by usev of a jig, well known in the coal industry as an apparatus for purities, the principle of which is based onthe difference in specific gravity of coal and rock or slate. This separation in the preparation of domestic sizes of anthracite is accomplished in a large tank filled with water. The action of a plunger about two feet below the surface I floats the coal to the surface, whence it can be removed. Instead of water, the jig is filled with the ammonium persulphate solution when it is desired to treat coal for the purpose.

of removing the discoloration.

The ammonium persulphate solution can be recovered and be reused until it becomes too 1 separating coal from im- A heavily contaminated with substances dis'-- solved from the coal, the concentration of the solution being maintained by the periodic addition of small quantities of ammonium persulghate, if necessary.

arious changes may be made in the procedure employed herein without departing from the invention or sacrificing any of the advantages thereof.

I claim:

The method of restoring the luster and improving the appearance of discolored coal which comprises treating it with a solution of ammonium persulphate. V

In testimony whereof I aflix my si nature.

ERNEST VICTOR COLLIN JR. 

